> On Mar 14, 2017, at 12:25 PM, Timo Kinnunen <timo.kinnu...@gmail.com> wrote: > > Hi, > > Maybe rather than “an ugly waste of memory” which sounds somewhat negative, > we could instead call it “an honestly assessed true resource cost”? >
Yuck! I'm imagining opening 32k file descriptors that represent sockets in e.g. a high performance asynchronous Jetty web server and finding that it consumes new long[65536] = 65536 * 8 bytes * 32768 ~= 18GB just in "fake garbage" to pressure out file descriptors. Sure sounds negative to me! > Besides, this amount wouldn’t have to be set in stone. It could be easily > increased or decreased in response to resource pressures. Lots of ergonomics > options here. In fact you’d never need more memory for this than what the > maximum amount is that’s available for new allocations. And it turns out > you’ll always have that much memory available by definition, so really no > memory would have to be wasted at all. > > > > Sent from Mail for Windows 10 > > From: Andrew Haley > Sent: Tuesday, March 14, 2017 19:03 > To: Timo Kinnunen; Hans Boehm; Uwe Schindler > Cc: core-libs-dev > Subject: Re: RFR 9: 8165641 : Deprecate Object.finalize > > On 14/03/17 14:01, Timo Kinnunen wrote: > >> File handles aren’t that scarce of a resource, really, at least on >> Windows. > > I've seen processes running out of file handles. It is possible to > change the per-process limit. And, of course, there is a lot of > hidden context in the kernel and device drivers. > >> On Windows threads are a lot scarcer resource than file handles, and >> I don’t recall anyone suggesting Java’s GC wasn’t suitable for >> managing that limited but crucially important resource. > > Java's GC isn't used for managing threads. > >> The question should then be, what makes threads so much easier to >> manage than file handles and how can we make file handles be more >> like threads? > > They're not. > >> Food for thought: threads need a big stack which means a lot of >> memory, but a file handle might be just 8 bytes which is hard to >> keep track of. So, change the storage of file handles to use slot-0 >> of new long[65536]; > > I did try that, and it does work, but it's an ugly waste of memory. > > Andrew. >
